I am developing a gallery which allows users to post photos, comments, vote and do many other tasks.
Now I think that it is correct to allow users to unsubscribe and remove all their data if they want to. However it is difficult to allow such a thing because you run the risk to break your application (e.g. what should I do when a comment has many replies? what should I do with pages that have many revisions by different users?).
Photos can be easily removed, but for other data (i.e. comments, revisions...) I thought that there are three possibilities:
assign it to the admin
assign it to a user called "removed-user"
mantain the current associations (i.e. the user ID) and only rename user's data (e.g. assign a new username such as "removed-user-24" and a non-existent e-mail such as "noreply-removed-user-24#mysite.com"
What are the best practices to follow when we allow users to remove their accounts? How do you implement them (particularly in Rails)?
I've typically solved this type of problem by having an active flag on user, and simply setting active to false when the user is deleted. That way I maintain referential integrity throughout the system even if a user is "deleted". In the business layer I always validate a user is active before allowing them to perform operations. I also filter inactive users when retrieving data.
The usual thing to do is instead of deleting them from a database, add a boolean flag field and have it be true for valid users and false for invalid users. You will have to add code to filter on the flag. You should also remove all relevant data from the user that you can. The primary purpose of this flag is to keep the links intact. It is a variant of the renaming the user's data, but the flag will be easier to check.
Ideally in a system you would not want to "hard delete" data. The best way I know of and that we have implemented in past is "soft delete". Maintain a status column in all your data tables which ideally refers to the fact whether the row is active or not. Any row when created is "Active" by default; however as entries are deleted; they are made inactive.
All select queries which display data on screen filter results for only "active records". This way you get following advantages:
1. Data Recovery is possible.
2. You can have a scheduled task on database level, which can take care of hard deletes of once in a way; if really needed. (Like a SQL procedure or something)
3. You can have an admin screen to be able to decide which accounts, entries etc you'd really want to mark for deletion
4. A temperory disabling of account can also be implemented with same solution.
In prod environments where I have worked on, a hard delete is a strict No-No. Infact audits are maintained for deletes also. But if application is really small; it'd be upto user.
I would still suggest a "virtual delete" or a "soft delete" with periodic cleanup on db level; which will be faster efficient and optimized way of cleaning up.
I generally don't like to delete anything and instead opt to mark records as deleted/unpublished using states (with AASM i.e. acts as state machine).
I prefer states and events to just using flags as you can use events to update attributes and send emails etc. in one foul swoop. Then check states to decide what to do later on.
HTH.
I would recommend putting in a delete date field that contains the date/time the user unsubscribed - not only to the user record, but to all information related to that user. The app should check the field prior to displaying anything. You can then run a hard delete for all records 30 days (your choice of time) after the delete date. This will allow the information not to be shown (you will probably need to update the app in a few places), time to allow the user to re-subscribe (accidental or rethinking) and a scheduled process to delete old data. I would remove ALL information about the member and any related comments about the member or their prior published data (photos, etc.)
I am sure it changing lot since update with Data Protection and GDPR, etc.
the reason I found this page as I was looking for advice because of new Apply policy on account deletion requirements extended https://developer.apple.com/news/?id=i71db0mv
We are using Ruby on Rails right now. Your answers seem a little outdated? or not or still useful right now
I was thinking something like that
create a new table “old_user_table” with old user_id , First name, Second name, email, and booking slug.
It will allow keep all users who did previous booking. And deleted their user ID in the app. We need to keep all records for booking for audit purpose in the last 5 years in the app.
the user setup with this app, the user but never booking, then the user will not transfer to “old_user_table” cos the user never booking.
Does it make sense? something like that?
Related
I've read into Cancan and Pundit (also Devise) for managing users in a Rails App. But I wanted to know if something was possible.
Basically, I want to have users change/add lines in a table (using SQLite at the moment, but will be moving to SQL in the future - call them entries). But before it gets added to the actual table, it gets sent to the admin for approval. Then the admin can just hit 'approve' and the statement gets run.
I'm just confused about how to hold the statement and then when approved, the statement runs. Any information would be appreciated.
By statement, do you mean that your users are actually writing the SQL themselves?
If not, I'd setup a second model identical to your first that acts like a queue of some sort that holds the proposed changes/additions. This way, you'll be able to compare the old and new statements if necessary, and, when approved, you'll be able to perform the create/update magic on your original model.
Hope this gives you some ideas!
I am trying to create an application which will provide IT services for different organizations.
I have a long form for creating a user where I have to search all users within that organization through LDAP. This turns out to be a time consuming process. I can search all users and later put them into a list and use that list in a different situation. But the problem is that at the same time any administrator can modify or delete a user. I have thought of putting the list into an application scoped bean. But I have a different organization as well, which has totally different set of users.
What is the appropriate solution in such a situation?
I would say this is not something that can be handled by the scope if you are running multiple instances of a JSF application that all access a single database.
This should be handled by a lock on the object in the database, i.e. when you load the editing view for a user, the user object is locked for editing to the others (like a boolean column named locked). Saving or canceling editing, releases the lock (or it expires if the user forgets to do any of it).
Application scoped data are visible to all users of your application. That is, if you put some list in application scope, and later reference it in view, it will be the same instance for every user. Also, you should beware of severe concurrency issues imposed by such approach.
Most probably, you scoping problems will end when you'll put your list of users in session scope, where it most naturally fits. You'll load the list of users of a particular organization when a user with appropriate rights demands it in some view.
From this point you'll face the actual problems that you're worried of, and those are problems that arise in a multiuser environment concurrently accessing shared resources (like administrators modifying users in your example). One of the things that you're afraid of, as it can be followed from your question, is the 'last commit wins' strategy, under which edits made in time by another users before the last user committed the edits will be lost, or overwritten, by the last commit.
This type of problems can be solved by introducing some type of 'locking' on the database level. Basically there are two types of locking: optimistic and pessimistic.
What Is proposed in another answer is an example of pessimistic locking, under which no one is allowed to access the data unless database lock is released. The seip is as follows: user who is going to update the data places an exclusive lock preventing other users from manipulating data until the lock is released. The idea behind is that the users will update the database resources synchronously and that possibility must be ruled out no matter how frequent those conflicting updates actually happen.
Another option - optimistic locking assumes that many users can access and modify data simultaneously, without locking the database resources. This is typically achieved by storing record version in the database. When a conflict occurs, a user can be prompted about that, preventing information loss. The idea behind is that though conflicting updates are possible, they will in fact be rare, and in any case the user will be notified of that conflict.
Note that the setup without locking, or 'last commit wins' strategy is basically the same as optimistic locking, when the final user always chooses to overwrite the data.
As you can see, there are some approaches to choose from. So first learn about them yourself, then maybe your not-so-like-question will vanish. And if not - you'll be able to come back and post a new question on concrete topic with concrete problem so that we won't speculate but will concentrate on helping you.
I'm using acts_as_taggable_on for tagging items across my system so that they're easily searchable.
Now I have a UX problem: I'm noticing lots of places where users choose certain minor states (for example, closing a one-time help box or moving to the next javascript-run step in a given page). We have here situations that are both too minor/numerous/dynamic/fast-changing to be put into a database table (imagine having to migrate with every UX change!), and that there is a need to persist some of these choices beyond the session.
In this case, is there anything wrong with using tags to store these simple decisions? For example, user.set_tags_on(:ui, "closed_index_help") or user.set_tags_on(:ui, "tutorial_1_done"), then showing/hiding these elements in the future by looking at the user's ui_list.
Are there drawbacks to this I'm not considering or is this a prudent way to go?
Another way might be to store the information in the SESSION. You will of course have to migrate the session information to be stored in the DB rather than the cookie, but at least that way - you only have to retrieve the session once.
I have a Comment model in my app but am encountering a lot of problematic postings that I have to remove manually.
What I want to do is add a "flag for moderator attention" feature so that users of the app have the ability to remove a comment from view without my need to review all content in the app.
I'm thinking that after a comment has been flagged three times, I will remove it from view automatically and then when I have a chance to review these postings I will decide whether to allow them or permanently remove them from view.
What I'm having trouble with is how to implement this.
Should I have a separate table that records all items that have been flagged?
Or should I have a "flag count" field as part of the Comment table that keeps track of how many times a comment has been flagged?
A separate table would allow me to keep track of detailed information about the flagging actions - who is flagging, which IP they are flagging from, etc. This is what I'm leaning towards.
But perhaps a gem or plugin already exists that does this type of thing?
I don't know of any plugin. I like the solution you are leaning towards.
If you want to hide the comment after three flaggings have been created for it, you need to keep track of who created them, so people can flag just once.
I'd create a flag resource (which can hold any kind of flags your users can assign to particular comment), then a flagging resource which connects flags with comments and holds information about the entity which is responsible for flagging (which could be a user or a user represented by IP).
Every comment will then have many flaggings.
You can use state machine to change the status of a comment to "to_be_revised" or something similar after three flaggings have been added. State machine (aasm_state_machine or the one which is now incorporated directly into Rails) will also provide you with named_scopes for groups of comments with the same state.
After revision, you can set the state to "published" again and delete all the flaggings or to "unpublishable" and so hide it forever.
Perhaps the acts-as-flaggable plugin would work.
I'm developing a webapp that allows the editing of records. There is a possibility that two users could be working on the same screen at a time and I want to minimise the damage done, if they both click save.
If User1 requests the page and then makes changes to the Address, Telephone and Contact Details, but before he clicks Save, User2 requests the same page.
User1 then clicks save and the whole model is updated using TryUpdateModel(), if User2 simply appends some detail to the Notes field, when he saves, the TryUpdateModel() method will overwrite the new details User1 saved, with the old details.
I've considered storing the original values for all the model's properties in a hidden form field, and then writing a custom TryUpdateModel to only update the properties that have changed, but this feels a little too like the Viewstate we've all been more than happy to leave behind by moving to MVC.
Is there a pattern for dealing with this problem that I'm not aware of?
How would you handle it?
Update: In answer to the comments below, I'm using Entity Framework.
Anthony
Unless you have any particular requirements for what happens in this case (e.g. lock the record, which of course requires some functionality to undo the lock in the event that the user decides not to make a change) I'd suggest the normal approach is an optimistic lock:
Each update you perform should check that the record hasn't changed in the meantime.
So:
Put an integer "version" property or a guid / rowversion on the record.
Ensure this is contained in a hidden field in the html and is therefore returned with any submit;
When you perform the update, ensure that the (database) record's version/guid/rowversion still matches the value that was in the hidden field [and add 1 to the "version" integer when you do the update if you've decided to go with that manual approach.]
A similar approach is obviously to use a date/time stamp on the record, but don't do that because, to within the accuracy of your system clock, it's flawed.
[I suggest you'll find fuller explanations of the whole approach elsewhere. Certainly if you were to google for information on NHibernate's Version functionality...]
Locking modification of a page while one user is working on it is an option. This is done in some wiki software like dokuwiki. In that case it will usually use some javascript to free the lock after 5-10 minutes of inactivity so others can update it.
Another option might be storing all revisions in a database so when two users submit, both copies are saved and still exist. From there on, all you'd need to do is merge the two.
You usually don't handle this. If two users happen to edit a document at the same time and commit their updates, one of them wins and the other looses.
Resources lockout can be done with stateful desktop applications, but with web applications any lockout scheme you try to implement may only minimize the damage but not prevent it.
Don't try to write an absolutely perfect and secure application. It's already good as it is. Just use it, probably the situation won't come up at all.
If you use LINQ to SQL as your ORM it can handle the issues around changed values using the conflicts collection. However, essentially I'd agree with Mastermind's comment.